龈上洁治术恰当的操作应是()
A.改良握笔式执持器械
B.支点松弛远离术区
C.层层刮削牙石
D.洁治器的刃部多放在牙石中部
E.用力方向向根方
参考答案:A
能通过化学反应使溴水褪色,又能使酸性高锰酸钾溶液褪色的是
A.苯
B.乙炔
C.乙烷
D.聚乙烯
______ I’ll be in ten more years? [ ]
A. What do you think
B. Do you think what
C. When do you think
D. Do you think when